Evidence for an alternative fatty acid desaturation pathway increasing cancer plasticity.

Most tumours have an aberrantly activated lipid metabolism1,2 that enables them to synthesize, elongate and desaturate fatty acids to support proliferation. However, only particular subsets of cancer cells are sensitive to approaches that target fatty acid metabolism and, in particular, fatty acid desaturation3. This suggests that many cancer cells contain an unexplored plasticity in their fatty acid metabolism. Here we show that some cancer cells can exploit an alternative fatty acid desaturation pathway. We identify various cancer cell lines, mouse hepatocellular carcinomas, and primary human liver and lung carcinomas that desaturate palmitate to the unusual fatty acid sapienate to support membrane biosynthesis during proliferation. Accordingly, we found that sapienate biosynthesis enables cancer cells to bypass the known fatty acid desaturation pathway that is dependent on stearoyl-CoA desaturase. Thus, only by targeting both desaturation pathways is the in vitro and in vivo proliferation of cancer cells that synthesize sapienate impaired. Our discovery explains metabolic plasticity in fatty acid desaturation and constitutes an unexplored metabolic rewiring in cancers.

Pembrolizumab in combination with gemcitabine and cisplatin compared with gemcitabine and cisplatin alone for patients with advanced biliary tract cancer (KEYNOTE-966): a randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: Biliary tract cancers, which arise from the intrahepatic or extrahepatic bile ducts and the gallbladder, generally have a poor prognosis and are rising in incidence worldwide. The standard-of-care treatment for advanced biliary tract cancer is chemotherapy with gemcitabine and cisplatin. Because most biliary tract cancers have an immune-suppressed microenvironment, immune checkpoint inhibitor monotherapy is associated with a low objective response rate. We aimed to assess whether adding the immune checkpoint inhibitor pembrolizumab to gemcitabine and cisplatin would improve outcomes compared with gemcitabine and cisplatin alone in patients with advanced biliary tract cancer. METHODS: KEYNOTE-966 was a randomised, double-blind, placebo-controlled, phase 3 trial done at 175 medical centres globally. Eligible participants were aged 18 years or older; had previously untreated, unresectable, locally advanced or metastatic biliary tract cancer; had disease measurable per Response Evaluation Criteria in Solid Tumours version 1.1; and had an Eastern Cooperative Oncology Group performance status of 0 or 1. Eligible participants were randomly assigned (1:1) to pembrolizumab 200 mg or placebo, both administered intravenously every 3 weeks (maximum 35 cycles), in combination with gemcitabine (1000 mg/m2 intravenously on days 1 and 8 every 3 weeks; no maximum duration) and cisplatin (25 mg/m2 intravenously on days 1 and 8 every 3 weeks; maximum 8 cycles). Randomisation was done using a central interactive voice-response system and stratified by geographical region, disease stage, and site of origin in block sizes of four. The primary endpoint of overall survival was evaluated in the intention-to-treat population. The secondary endpoint of safety was evaluated in the as-treated population. This study is registered at ClinicalTrials.gov, NCT04003636. FINDINGS: Between Oct 4, 2019, and June 8, 2021, 1564 patients were screened for eligibility, 1069 of whom were randomly assigned to pembrolizumab plus gemcitabine and cisplatin (pembrolizumab group; n=533) or placebo plus gemcitabine and cisplatin (placebo group; n=536). Median study follow-up at final analysis was 25·6 months (IQR 21·7-30·4). Median overall survival was 12·7 months (95% CI 11·5-13·6) in the pembrolizumab group versus 10·9 months (9·9-11·6) in the placebo group (hazard ratio 0·83 [95% CI 0·72-0·95]; one-sided p=0·0034 [significance threshold, p=0·0200]). In the as-treated population, the maximum adverse event grade was 3 to 4 in 420 (79%) of 529 participants in the pembrolizumab group and 400 (75%) of 534 in the placebo group; 369 (70%) participants in the pembrolizumab group and 367 (69%) in the placebo group had treatment-related adverse events with a maximum grade of 3 to 4. 31 (6%) participants in the pembrolizumab group and 49 (9%) in the placebo group died due to adverse events, including eight (2%) in the pembrolizumab group and three (1%) in the placebo group who died due to treatment-related adverse events. INTERPRETATION: Based on a statistically significant, clinically meaningful improvement in overall survival compared with gemcitabine and cisplatin without any new safety signals, pembrolizumab plus gemcitabine and cisplatin could be a new treatment option for patients with previously untreated metastatic or unresectable biliary tract cancer. FUNDING: Merck Sharp & Dohme, a subsidiary of Merck & Co, Rahway, NJ, USA.

Molecular Markers of Response to Anti-PD1 Therapy in Advanced Hepatocellular Carcinoma.

BACKGROUND & AIMS: Single-agent anti-PD1 checkpoint inhibitors convey outstanding clinical benefits in a small fraction (∼20%) of patients with advanced hepatocellular carcinoma (aHCC) but the molecular mechanisms determining response are unknown. To fill this gap, we herein analyze the molecular and immune traits of aHCC in patients treated with anti-PD1. METHODS: Overall, 111 tumor samples from patients with aHCC were obtained from 13 centers before systemic therapies. We performed molecular analysis and immune deconvolution using whole-genome expression data (n = 83), mutational analysis (n = 72), and histologic evaluation with an endpoint of objective response. RESULTS: Among 83 patients with transcriptomic data, 28 were treated in frontline, whereas 55 patients were treated after tyrosine kinase inhibitors (TKI) either in second or third line. Responders treated in frontline showed upregulated interferon-γ signaling and major histocompatibility complex II-related antigen presentation. We generated an 11-gene signature (IFNAP), capturing these molecular features, which predicts response and survival in patients treated with anti-PD1 in frontline. The signature was validated in a separate cohort of aHCC and >240 patients with other solid cancer types where it also predicted response and survival. Of note, the same signature was unable to predict response in archival tissue of patients treated with frontline TKIs, highlighting the need for fresh biopsies before immunotherapy. CONCLUSION: Interferon signaling and major histocompatibility complex-related genes are key molecular features of HCCs responding to anti-PD1. A novel 11-gene signature predicts response in frontline aHCC, but not in patients pretreated with TKIs. These results must be confirmed in prospective studies and highlights the need for biopsies before immunotherapy to identify biomarkers of response.

Human pancreatic cancer patients with Epithelial-to-Mesenchymal Transition and an aggressive phenotype show a disturbed balance in Protein Phosphatase Type 2A expression and functionality.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) has a low survival, its incidence is rising and little therapeutic improvements are expected in the near future. It has been observed that Epithelial-to-Mesenchymal transition (EMT) contributes (including in PDAC) to a more aggressive cancer phenotype. Additionally, largely unexplored, studies indicate a mechanistic interplay between Protein Phosphatase Type 2A (PP2A) enzymes and EMT that could offer treatment opportunities. The aim was to investigate the relation of a PP2A expression signature (encompassing all PP2A subunits, endogenous inhibitors and activators) with EMT and aggressive pancreatic cancer, and to discuss possible implications. METHODS: We retrieved different PDAC expression datasets from NCBI to capture the variation in patients, and analyzed these using datamining, survival analysis, differential gene and protein expression. We determined genes highly associated with aggressive PDAC. For in vitro evaluation, Panc-1 cells were treated with the pharmacologic PP2A inhibitor Okadaic Acid (OA). Additionally, two OA-resistant Panc-1 clones were developed and characterized. RESULTS: In patients, there is a strong correlation between EMT and aggressive PDAC, and between aggressive PDAC and PP2A, with a significant upregulation of PP2A inhibitor genes. Several PP2A genes significantly correlated with decreased survival. In vitro, short-term exposure to OA induced EMT in Panc-1 cells. This shift towards EMT was further pronounced in the OA-resistant Panc-1 clones, morphologically and by pathway analysis. Proteomic analysis and gene sequencing showed that the advanced OA-resistant model most resembles the clinical PDAC presentation (with EMT signature, and with several specific PP2A genes upregulated, and others downregulated). CONCLUSIONS: We demonstrated a strong association between EMT, altered PP2A expression and aggressive PDAC in patients. Also, in vitro, PP2A inhibition induces EMT. Overall, statistics suggests the mechanistic importance of PP2A dysregulation for PDAC progression. Translationally, our observations indicate that pharmacologic restoration of PP2A activity could be an attractive therapeutic strategy to block or reverse progression.

Genotype specific and microbiome effects of hypoxia in the model organism Daphnia magna.

The fitness of the host is highly influenced by the interplay between the host and its associated microbiota. The flexible nature of these microbiota enables them to respond swiftly to shifts in the environment, which plays a key role in the host's capacity to withstand environmental stresses. To understand the role of the microbiome in host tolerance to hypoxia, one of the most significant chemical changes occurring in water ecosystems due to climate change, we performed a reciprocal gut transplant experiment with the freshwater crustacean Daphnia magna. In a microbiome transplant experiment, two genotypes of germ-free recipients were inoculated with gut microbiota from Daphnia donors of their own genotype or from the other genotype, that had been either pre-exposed to normoxic or hypoxic conditions. We found that D. magna individuals had a higher survival probability in hypoxia if their microbiome had been pre-exposed to hypoxia. The bacterial communities of the recipients changed over time with a reduction in alpha diversity, which was stronger when donors were pre-exposed to a hypoxic environment. While donor genotype had no influence on the long-term survival probability in hypoxia, donor genotypes was the most influential factor of the microbial community 3 days after the transplantation. Our results indicate that microbiome influencing factors mediate host fitness in a hypoxic environment in a time depending way.

Robotic Versus Laparoscopic Hepatectomy: A Single Surgeon Experience of 629 Consecutive Minimally Invasive Liver Resections.

BACKGROUND: Robotic surgery has the potential to broaden the indications for minimally invasive liver surgery owing to its technical advantages. This paper compares our experience with robotic liver surgery (RLS) with conventional laparoscopic liver surgery (LLS). METHODS: All consecutive liver resections between October 2011 and October 2022 were selected from our prospective database to be included in this cohort study. Patients who underwent RLS were compared with a LLS group for operative and postoperative outcomes. RESULTS: In total, 629 patients were selected from our database, including 177 patients who underwent a RLS and 452 patients who had LLS. Colorectal liver metastasis was the main indication for surgery in both groups. With the introduction of RLS, the percentage of open resections decreased significantly (32.6% from 2011 to 2020 vs. 11.5% from 2020 onward, P < 0.001). In the robotic group, redo liver surgery was more frequent (24.3% vs. 16.8%, P = 0.031) and the Southampton difficulty score was higher (4 [IQR 4 to 7] vs. 4 [IQR 3 to 6], P = 0.02). Median blood loss was lower (30 vs. 100 ml, P < 0.001), and postoperative length of stay (LOS) was shorter in the robotic group (median 3 vs. 4 days, P < 0.001). There was no significant difference in postoperative complications. Cost related to the used instruments and LOS was significantly lower in the RLS group (median €1483 vs. €1796, P < 0.001 and €1218 vs. €1624, P < 0.001, respectively), while cost related to operative time was higher (median €2755 vs. €2470, P < 0.001). CONCLUSIONS: RLS may allow for a higher percentage of liver resections to be completed in a minimally invasive way with lower blood loss and a shorter LOS.

Closing spontaneous portosystemic shunts in cirrhosis: Does it make sense? Does it work? What does it take?

Spontaneous portosystemic shunts (SPSS) are an often neglected cause of hepatic encephalopathy associated with cirrhosis. Nowadays, SPSS are considered as radiological biomarkers of clinically significant portal hypertension rather than the previous dogmatic perceived decompressive vessels. SPSS are not rare as they can be diagnosed in over 60% of the patients with cirrhosis by mere contrast-enhanced CT. Moreover, they are clinically relevant since they impact on all portal hypertensive related complications, in particular medically refractory HE, and represent an independent predictor of decompensation and mortality in cirrhosis, irrespective of the type of SPSS. Taken together, these elements warrant strategies to target these shunts directly which is currently is achieved via interventional radiology embolization. In this review, we discuss why it makes sense to tackle SPSS, how to do it and what it takes to do it right based on aggregated literature.

Development and external validation of a prediction model for overall survival after resection of distal cholangiocarcinoma.

BACKGROUND: Various prognostic factors are associated with overall survival (OS) after resection of distal cholangiocarcinoma (dCCA). The objective of this study was to develop and validate a prediction model for 3-year OS after pancreatoduodenectomy for dCCA. METHODS: The derivation cohort consisted of all patients who underwent pancreatoduodenectomy for dCCA in the Netherlands (2009-2016). Clinically relevant variables were selected based on the Akaike information criterion using a multivariate Cox proportional hazards regression model, with model performance being assessed by concordance index (C-index) and calibration plots. External validation was performed using patients from the Belgium Cancer Registry (2008-2016), and patients from two university hospitals of Southampton (U.K.) and Verona (Italy). RESULTS: Independent prognostic factors for OS in the derivation cohort of 454 patients after pancreatoduodenectomy for dCCA were age (HR 1.02, 95% CI 1.01-1.03), pT (HR 1.43, 95% CI 1.07-1.90) and pN category (pN1: HR 1.78, 95% CI 1.37-2.32; pN2: HR 2.21, 95% CI 1.63-3.01), resection margin status (HR 1.79, 95% CI 1.39-2.29) and tumour differentiation (HR 2.02, 95% CI 1.62-2.53). The prediction model was based on these prognostic factors. The optimism-adjusted C-indices were similar in the derivation cohort (0.69), and in the Belgian (0.66) and Southampton-Verona (0.68) validation cohorts. Calibration was accurate in the Belgian validation cohort (slope = 0.93, intercept = 0.12), but slightly less optimal in the Southampton-Verona validation cohort (slope = 0.88, intercept = 0.32). Based on this model, three risk groups with different prognoses were identified (3-year OS of 65.4%, 33.2% and 11.8%). CONCLUSIONS: The prediction model for 3-year OS after resection of dCCA had reasonable performance in both the derivation and geographically external validation cohort. Calibration slightly differed between validation cohorts. The model is readily available via www. pancreascalculator.com to inform patients from Western European countries on their prognosis, and may be used to stratify patients for clinical trials.

Addition of Y-90 radioembolization increases tumor response and local disease control in hepatocellular carcinoma patients receiving sorafenib.

PURPOSE: To compare the treatment response and progression-free survival (PFS) in advanced hepatocellular carcinoma (HCC) patients who received sorafenib treatment either alone or combined with radioembolization (RE). METHODS: Follow-up images of the patients treated within a multicenter phase II trial (SORAMIC) were assessed by mRECIST. A total of 177 patients (73 combination arm [RE + sorafenib] and 104 sorafenib arm) were included in this post-hoc analysis. Response and progression characteristics were compared between treatment arms. Survival analyses were done to compare PFS and post-progression survival between treatment arms. Multivariate Cox regression analysis was used to compare survival with factors known to influence PFS in patients with HCC. RESULTS: The combination arm had significantly higher objective response rate (61.6% vs. 29.8%, p < 0.001), complete response rate (13.7% vs. 3.8%, p = 0.022), and a trend for higher disease control rate (79.2% vs. 72.1%, p = 0.075). Progression was encountered in 116 (65.5%) patients and was more common in the sorafenib arm (75% vs. 52.0%, p = 0.001). PFS (median 8.9 vs. 5.4 months, p = 0.022) and hepatic PFS were significantly better in the combination arm (9.0 vs. 5.7 months, p = 0.014). Multivariate analysis confirmed the treatment arm as an independent predictor of PFS. CONCLUSION: In advanced HCC patients receiving sorafenib, combination with RE has an additive anticancer effect on sorafenib treatment resulting in a higher and longer tumor response. However, the enhanced response did not translate into prolonged survival. Better patient selection and superselective treatment could improve outcomes after combination therapy.

One-stage laparoscopic parenchymal sparing liver resection for bilobar colorectal liver metastases: safety, recurrence patterns and oncologic outcomes.

BACKGROUND AND PURPOSE: Laparoscopic liver resections (LLR) of bilobar colorectal liver metastases (CRLM) are challenging and the safety and long-term outcomes are unclear. In this study, the short- and long-term outcomes and recurrence patterns of one-stage LLR for bilobar CRLM were compared to single laparoscopic resection for CRLM. METHODS: This single-center study consisted of all patients who underwent a parenchymal sparing LLR for CRLM between October 2011 and December 2018. Demographics, perioperative outcomes, short-term outcomes, oncologic outcomes and recurrence patterns were compared. Data were retrieved from a prospectively maintained database. RESULTS: Thirty six patients underwent a LLR for bilobar CRLM and ninety patients underwent a single LLR. Demographics were similar among groups. More patients received neoadjuvant chemotherapy in the bilobar group (55.6% vs 34.4%, P = 0.03). There was no difference in conversion rate, R0 resection and transfusion rate. Blood loss and operative time were higher in the bilobar group (250 ml (IQR 150-450) vs 100 ml (IQR 50-250), P < 0.001 and 200 min (IQR 170-230) vs 130 min (IQR 100-165), P < 0.001) and hospital stay was longer (5 days (IQR 4-7) vs 4 days (IQR 3-6), P = 0.015). The bilobar group had more technically major resections (88.9% vs 56.7%, P < 0.001). Mortality was nil in both groups and major morbidity was similar (2.8% vs 3.3%, P = 1.0). There was no difference in recurrence pattern. Overall survival (OS) was similar (1 yr: 96% in both groups and 5 yr 76% vs 66%, P = 0.49), as was recurrence-free survival (RFS) (1 yr: 64% vs 73%, 3 yr: 38 vs 42%, 5 yr: 38% vs 28%, P = 0.62). CONCLUSION: In experienced hands, LLR for bilobar CRLM can be performed safely with similar oncologic outcomes as patients who underwent a single LLR for CRLM.

A Comparative Study of an Integrated Ultrasonic/Bipolar Sealing Device Versus an Articulating Bipolar Sealing Device for Laparoscopic Liver Surgery.

BACKGROUND: Sealing devices (SD) seal and cut tissue through different energy modalities, and are routinely used in laparoscopic liver surgery (LLS). The aim of this study is to compare the outcome of Thunderbeat (TB), an integrated ultrasonic/bipolar SD, versus Enseal (ES), an articulating bipolar SD, in LLS. METHODS: A retrospective analysis was conducted in a single center from December 2013 to September 2020. The primary endpoint was difference in blood loss (BL) between ES and TB. Secondary endpoints were complications, operative time, hospital stay, and 90-day mortality. RESULTS: 352 patients were identified: TB (n = 105) and ES (n = 247). Median BL was significantly lower with TB (50 mL [20-120]) compared to ES (100 mL [50-250]) (p < 0.0001). Significant differences were identified for median operative time (TB 115 min [45-300]) vs. ES 140 min [40-370]; p = 0.0008) and median hospital stay (TB 2 days [1-4] vs. ES 4 days [3-6]; p < 0.0001). No major differences were encountered for postoperative bleeding (TB 0% vs. ES 1%; p = 0.5574), biliary leak (TB 1% vs. ES 2%; p = 1.0000), and 90-day mortality (TB 0% vs. ES 1%; p = 1.0000). CONCLUSION: The integrated ultrasonic/bipolar SD is superior to the articulating bipolar SD in LLS for intraoperative BL without an increase in complications.

Laparoscopic liver resection for colorectal liver metastases: retrospective analysis of prognostic factors and oncological outcomes in a single-center cohort.

PURPOSE: Laparoscopic liver resection (LLR) has gained acceptance as an effective treatment for colorectal liver metastases (CRLM) in selected patients, providing similar oncologic outcomes compared to open liver resection (OLR). The aim of this study was to determine prognostic factors for survival outcomes associated with LLR for CRLM. METHODS: A single-center retrospective analysis of a prospectively maintained database was performed. The inclusion period ranged from September 2011 until mid-March 2020. RESULTS: Two hundred consecutive LLRs were included. The 5-year overall survival (OS) and disease-free survival (DFS) rates equalled 54.8% and 49%, respectively. A pushing (HR = 5.42, 95% CI 1.56-18.88, p = 0.008), as well as a replacement (3.87, 1.05-14.2, p = 0.04) growth pattern of the CRLM, poor differentiation of the primary colorectal cancer (CRC) (3.72, 1.72-8.07, p < 0.001) and administration of neoadjuvant chemotherapy (NAC) (2.95, 1.28-6.8, p = 0.01) were identified as independent predictors of a worse OS. Requirement of more than 6 cycles of NAC (6.17, 2.37-16.03, p < 0.001), a replacement (4.96, 1.91-12.87, p < 0.001), as well as a pushing (4.3, 1.68-11, p = 0.002) growth pattern of the CRLM and poor differentiation of the primary CRC (2.61, 1.31-5.2, p = 0.006) were identified as independent predictors of a worse DFS. CONCLUSION: LLR for CRLM offers adequate long-term oncologic outcomes. OS and DFS rates are negatively affected by the administration of NAC and by pathological features, including the differentiation grade of the primary CRC and the histological growth pattern of the CRLM.

Recanalization of portal axis after cavoportal hemitransposition in a liver transplant recipient with complete splanchnic thrombosis.

BACKGROUND: Diffuse splanchnic thrombosis may render standard LTx difficult or even technically impossible. A 19-year-old woman with acute-on-chronic Budd-Chiari syndrome and complete splanchnic thrombosis underwent conventional LTx. Only limited anatomical portal inflow could be restored, and urgent re-transplantation for recurrent splanchnic vein thrombosis became necessary. METHODS: At re-transplant, and in addition to the reestablishment of some portal inflow through the preserved original porto (native)-portal (graft) connection, a cavoportal shunt was created (first partial via 30% tapering of the vena cava, but eventually complete by total occlusion of the vena cava). RESULTS: The postoperative course was then uneventful, and interestingly, the native portomesenteric axis gradually reopened. Two years post-transplant, the liver graft is perfused via both physiological and non-physiological sources. Liver function is normal. There is no IVC syndrome and no residual PHT. She is leading a normal life. CONCLUSION: Creation of CPHT, in addition to the preservation of portal inflow from the native splanchnic system, should be considered in patients with diffuse splanchnic thrombosis, when sufficient physiological portal inflow cannot be restored at the time of LTx, but in whom the splanchnic circulation may reopen up later.

Autophagy-Related Chemoprotection against Sorafenib in Human Hepatocarcinoma: Role of FOXO3 Upregulation and Modulation by Regorafenib.

Early acquisition of sorafenib resistance is responsible for the dismal prognosis of advanced hepatocarcinoma (HCC). Autophagy, a catabolic process involved in liver homeostasis, has been associated with chemosensitivity modulation. Forkhead box O3 (FOXO3) is a transcription factor linked to HCC pathogenesis whose role on autophagy-related sorafenib resistance remains controversial. Here, we unraveled the linkage between autophagy and sorafenib resistance in HCC, focusing on the implication of FOXO3 and its potential modulation by regorafenib. We worked with two HepG2-derived sorafenib-resistant HCC in vitro models (HepG2S1 and HepG2S3) and checked HCC patient data from the UALCAN database. Resistant cells displayed an enhanced basal autophagic flux compared to HepG2, showing higher autophagolysosome content and autophagy markers levels. Pharmacological inhibition of autophagy boosted HepG2S1 and HepG2S3 apoptosis and subG1 cells, but reduced viability, indicating the cytoprotective role of autophagy. HCC samples displayed higher FOXO3 levels, being associated with shorter survival and autophagic genes expression. Consistently, chemoresistant in vitro models showed significant FOXO3 upregulation. FOXO3 knockdown suppressed autophagy and caused resistant cell death, demonstrating that overactivation of such pro-survival autophagy during sorafenib resistance is FOXO3-dependent; a cytoprotective mechanism that the second-line drug regorafenib successfully abolished. Therefore, targeting FOXO3-mediated autophagy could significantly improve the clinical efficacy of sorafenib.

Whole liver segmentation based on deep learning and manual adjustment for clinical use in SIRT.

PURPOSE: In selective internal radiation therapy (SIRT), an accurate total liver segmentation is required for activity prescription and absorbed dose calculation. Our goal was to investigate the feasibility of using automatic liver segmentation based on a convolutional neural network (CNN) for CT imaging in SIRT, and the ability of CNN to reduce inter-observer variability of the segmentation. METHODS: A multi-scale CNN was modified for liver segmentation for SIRT patients. The CNN model was trained with 139 datasets from three liver segmentation challenges and 12 SIRT patient datasets from our hospital. Validation was performed on 13 SIRT datasets and 12 challenge datasets. The model was tested on 40 SIRT datasets. One expert manually delineated the livers and adjusted the liver segmentations from CNN for 40 test SIRT datasets. Another expert performed the same tasks for 20 datasets randomly selected from the 40 SIRT datasets. The CNN segmentations were compared with the manual and adjusted segmentations from the experts. The difference between the manual segmentations was compared with the difference between the adjusted segmentations to investigate the inter-observer variability. Segmentation difference was evaluated through dice similarity coefficient (DSC), volume ratio (RV), mean surface distance (MSD), and Hausdorff distance (HD). RESULTS: The CNN segmentation achieved a median DSC of 0.94 with the manual segmentation and of 0.98 with the manually corrected CNN segmentation, respectively. The DSC between the adjusted segmentations is 0.98, which is 0.04 higher than the DSC between the manual segmentations. CONCLUSION: The CNN model achieved good liver segmentations on CT images of good image quality, with relatively normal liver shapes and low tumor burden. 87.5% of the 40 CNN segmentations only needed slight adjustments for clinical use. However, the trained model failed on SIRT data with low dose or contrast, lesions with large density difference from their surroundings, and abnormal liver position and shape. The abovementioned scenarios were not adequately represented in the training data. Despite this limitation, the current CNN is already a useful clinical tool which improves inter-observer agreement and therefore contributes to the standardization of the dosimetry. A further improvement is expected when the CNN will be trained with more data from SIRT patients.

[18F]AlF-NOTA-octreotide PET imaging: biodistribution, dosimetry and first comparison with [68Ga]Ga-DOTATATE in neuroendocrine tumour patients.

PURPOSE: The widespread use of gallium-68-labelled somatostatin analogue (SSA) PET, the current standard for somatostatin receptor (SSTR) imaging, is limited by practical and economic challenges that could be overcome by a fluorine-18-labelled alternative, such as the recently introduced [18F]AlF-NOTA-octreotide ([18F]AlF-OC). This prospective trial aimed to evaluate safety, dosimetry, biodistribution, pharmacokinetics and lesion targeting of [18F]AlF-OC and perform the first comparison with [68Ga]Ga-DOTATATE in neuroendocrine tumour (NET) patients. METHODS: Six healthy volunteers and six NET patients with a previous clinical [68Ga]Ga-DOTATATE PET were injected with an IV bolus of 4 MBq/kg [18F]AlF-OC. Healthy volunteers underwent serial whole-body PET scans from time of tracer injection up to 90 min post-injection, with an additional PET/CT at 150 and 300 min post-injection. In patients, a 45-min dynamic PET was acquired and three whole-body PET scans at 60, 90 and 180 min post-injection. Absorbed organ doses and effective doses were calculated using OLINDA/EXM. Normal organ uptake (SUVmean) and tumour lesion uptake (SUVmax and tumour-to-background ratio (TBR)) were measured. A lesion-by-lesion analysis was performed and the detection ratio (DR), defined as the fraction of detected lesions was determined for each tracer. RESULTS: [18F]AlF-OC administration was safe and well tolerated. The highest dose was received by the spleen (0.159 ± 0.062 mGy/MBq), followed by the urinary bladder wall (0.135 ± 0.046 mGy/mBq) and the kidneys (0.070 ± 0.018 mGy/MBq), in accordance with the expected SSTR-specific uptake in the spleen and renal excretion of the tracer. The effective dose was 22.4 ± 4.4 µSv/MBq. The physiologic uptake pattern of [18F]AlF-OC was comparable to [68Ga]Ga-DOTATATE. Mean tumour SUVmax was lower for [18F]AlF-OC (12.3 ± 6.5 at 2 h post-injection vs. 18.3 ± 9.5; p = 0.03). However, no significant differences were found in TBR (9.8 ± 6.7 at 2 h post-injection vs. 13.6 ± 11.8; p = 0.35). DR was high and comparable for both tracers (86.0% for [68Ga]Ga-DOTATATE vs. 90.1% for [18F]AlF-OC at 2 h post-injection; p = 0.68). CONCLUSION: [18F]AlF-OC shows favourable kinetic and imaging characteristics in patients that warrant further head-to-head comparison to validate [18F]AlF-OC as a fluorine-18-labelled alternative for gallium-68-labelled SSA clinical PET. TRIAL REGISTRATION: Clinicaltrials.gov : NCT03883776, EudraCT: 2018-002827-40.

Impact of liver tumour burden, alkaline phosphatase elevation, and target lesion size on treatment outcomes with 177Lu-Dotatate: an analysis of the NETTER-1 study.

PURPOSE: To assess the impact of baseline liver tumour burden, alkaline phosphatase (ALP) elevation, and target lesion size on treatment outcomes with 177Lu-Dotatate. METHODS: In the phase 3 NETTER-1 trial, patients with advanced, progressive midgut neuroendocrine tumours (NET) were randomised to 177Lu-Dotatate (every 8 weeks, four cycles) plus octreotide long-acting release (LAR) or to octreotide LAR 60 mg. Primary endpoint was progression-free survival (PFS). Analyses of PFS by baseline factors, including liver tumour burden, ALP elevation, and target lesion size, were performed using Kaplan-Meier estimates; hazard ratios (HRs) with corresponding 95% CIs were estimated using Cox regression. RESULTS: Significantly prolonged median PFS occurred with 177Lu-Dotatate versus octreotide LAR 60 mg in patients with low (< 25%), moderate (25-50%), and high (> 50%) liver tumour burden (HR 0.187, 0.216, 0.145), and normal or elevated ALP (HR 0.153, 0.177), and in the presence or absence of a large target lesion (diameter > 30 mm; HR, 0.213, 0.063). Within the 177Lu-Dotatate arm, no significant difference in PFS was observed amongst patients with low/moderate/high liver tumour burden (P = 0.7225) or with normal/elevated baseline ALP (P = 0.3532), but absence of a large target lesion was associated with improved PFS (P = 0.0222). Grade 3 and 4 liver function abnormalities were rare and did not appear to be associated with high baseline liver tumour burden. CONCLUSIONS: 177Lu-Dotatate demonstrated significant prolongation in PFS versus high-dose octreotide LAR in patients with advanced, progressive midgut NET, regardless of baseline liver tumour burden, elevated ALP, or the presence of a large target lesion. Clinicaltrials.gov : NCT01578239, EudraCT: 2011-005049-11.

Peptide receptor radionuclide therapy controls inappropriate calcitriol secretion in a pancreatic neuro-endocrine tumor: a case report.

BACKGROUND: Hypercalcemia of malignancy is not uncommon in patients with advanced stage cancer. In rare cases the cause of the hypercalcemia is excessive production of calcitriol, the active form of vitamin D. Although inappropriate tumoral secretion of calcitriol is typically associated with lymphomas and some ovarian germ cell tumors, we present a case of calcitriol overproduction-induced hypercalcemia due to a pancreatic neuroendocrine tumor. The high expression of somatostatin receptors on this neuroendocrine neoplasm opened up the opportunity to treat the patient with radiolabelled somatostatin analogs, which successfully controlled the refractory hypercalcaemia and calcitriol levels. This case documents a rare finding of refractory hypercalcaemia of underlying malignancy due to a calcitriol-producing pancreatic neuroendocrine tumor, responding to peptide receptor radionuclide therapy (PRRT). CASE PRESENTATION: A 57 years-old patient presented with back pain, general discomfort, polydipsia, polyuria, fatigue and recent weight loss of 10 kg. Clinical examination was normal and there was no relevant medical history. Biochemical evaluation showed hypercalcemia with markedly increased calcitriol levels. CT-thorax-abdomen and ultrasound guided biopsy revealed a pancreatic neuroendocrine tumor with multifocal liver metastases, suggesting that excessive overproduction of calcitriol by this neuroendocrine tumor was the cause of the refractory hypercalcemia. The patient was eligible for PRRT. Four cycles of 177Lu-DOTATATE PRRT resulted in a morphological response and a normalization of serum calcium levels, confirming the hypothesis of a calcitriol producing pancreatic neuroendocrine tumor. Progression of liver metastases warranted further therapy and temozolomide-capecitabine was started with morphological and biochemical (serum calcium, calcitriol) stabilization. CONCLUSION: Although up to 30-40% of gastroenteropancreatic neuroendocrine tumors are known to be functional (i.e. producing symptoms associated with the predominant hormone/peptide secreted), calcitriol secreting pancreatic neuroendocrine tumors are very rare. However, treatment with PRRT resulted in normalization of calcium and calcitriol levels, strongly supporting the hypothesis of a calcitriol-producing pancreatic neuroendocrine tumor.

Influence of pretreatment with everolimus or sunitinib on the subacute hematotoxicity of 177Lu-DOTATATE PRRT.

Background: Peptide receptor radionuclide therapy (PRRT) is a validated treatment for somatostatin receptor overexpressing neuroendocrine tumors (NETs). The NETTER-1 trial demonstrated a pronounced positive effect on progression-free-survival compared to high dose somatostatin analogs (SSAs), with a strong tendency toward overall survival benefit. Our aim was to investigate the influence of pretreatment with everolimus and/or sunitinib on subacute hematotoxicity of PRRT. To assess the influence of prior treatment with everolimus/sunitinib might be of clinical relevance due to the link between short-term hematotoxicity and increased incidence of late hematotoxicity.Material and methods: Our single-center retrospective study enrolled all patients treated with 177Lu-DOTATATE PRRT (1-4 cycles of 7.4 GBq), between November 2013 and July 2018. Patients were assigned to two groups according to their pretreatment: no targeted agents (N = 41), or targeted agents (everolimus, sunitinib or both; N = 41). The end point was subacute hematotoxicity, defined as the nadir value between the first administration until 3 months after the last administration, using the CTCAE 4.03 classification. The impact of splenectomy was also explored.Results: Eighty percent of patients had a primary gastroenteropancreatic NET. No statistically significant differences in severe subacute hematotoxicity were seen in the pretreated group vs. the naive group for hemoglobin (grade 3/4: 12% vs. 22%), neither for leucocytes (grade 3/4: 10% vs. 7%), neutrophils (grade 3/4: 5% vs. 7%), lymphocytes (grade 3/4: 49% vs. 37%) and platelets (grade 3/4: 15% vs. 15%). Furthermore, we observed significantly lower toxicity for total white blood cells, lymphocytes and platelets in the subgroup that had splenectomy (N = 12). Limitations of this study include the potential bias in lack of use of targeted agents in patients more susceptible to toxicity, and the limited number of patients and events.Conclusions: In a patient cohort with NET pretreated with everolimus and/or sunitinib, we could not demonstrate a significant effect of prior/pretreatment with everolimus and/or sunitinib on the subacute hematotoxicity of 177Lu-DOTATATE PRRT.

Molecular predictors of prevention of recurrence in HCC with sorafenib as adjuvant treatment and prognostic factors in the phase 3 STORM trial.

OBJECTIVE: Sorafenib is the standard systemic therapy for advanced hepatocellular carcinoma (HCC). Survival benefits of resection/local ablation for early HCC are compromised by 70% 5-year recurrence rates. The phase 3 STORM trial comparing sorafenib with placebo as adjuvant treatment did not achieve its primary endpoint of improving recurrence-free survival (RFS). The biomarker companion study BIOSTORM aims to define (A) predictors of recurrence prevention with sorafenib and (B) prognostic factors with B level of evidence. DESIGN: Tumour tissue from 188 patients randomised to receive sorafenib (83) or placebo (105) in the STORM trial was collected. Analyses included gene expression profiling, targeted exome sequencing (19 known oncodrivers), immunohistochemistry (pERK, pVEGFR2, Ki67), fluorescence in situ hybridisation (VEGFA) and immunome. A gene signature capturing improved RFS in sorafenib-treated patients was generated. All 70 RFS events were recurrences, thus time to recurrence equalled RFS. Predictive and prognostic value was assessed using Cox regression models and interaction test. RESULTS: BIOSTORM recapitulates clinicopathological characteristics of STORM. None of the biomarkers tested (related to angiogenesis and proliferation) or previously proposed gene signatures, or mutations predicted sorafenib benefit or recurrence. A newly generated 146-gene signature identifying 30% of patients captured benefit to sorafenib in terms of RFS (p of interaction=0.04). These sorafenib RFS responders were significantly enriched in CD4+ T, B and cytolytic natural killer cells, and lacked activated adaptive immune components. Hepatocytic pERK (HR=2.41; p=0.012) and microvascular invasion (HR=2.09; p=0.017) were independent prognostic factors. CONCLUSION: In BIOSTORM, only hepatocytic pERK and microvascular invasion predicted poor RFS. No mutation, gene amplification or previously proposed gene signatures predicted sorafenib benefit. A newly generated multigene signature associated with improved RFS on sorafenib warrants further validation. TRIAL REGISTRATION NUMBER: NCT00692770.